[rtems commit] rpc: misaligned address exception in get_myaddress.c

[Gedare Bloom]

Module:    rtems
Branch:    4.9
Commit:    344856b8adff03b48b2e2e83417e175189ba75b5
Changeset: http://git.rtems.org/rtems/commit/?id=344856b8adff03b48b2e2e83417e175189ba75b5

Author:    Jeffrey Hill <johill at lanl.gov>
Date:      Mon Feb 23 12:06:21 2015 -0500

rpc: misaligned address exception in get_myaddress.c

updates #2249 see #1401

---

 cpukit/librpc/src/rpc/get_myaddress.c | 53 +++++++++++++++++++++++++----------
 1 file changed, 38 insertions(+), 15 deletions(-)

diff --git a/cpukit/librpc/src/rpc/get_myaddress.c b/cpukit/librpc/src/rpc/get_myaddress.c
index 60357cf..1c7088f 100644
--- a/cpukit/librpc/src/rpc/get_myaddress.c
+++ b/cpukit/librpc/src/rpc/get_myaddress.c
@@ -45,13 +45,27 @@ static char *rcsid = "$FreeBSD: src/lib/libc/rpc/get_myaddress.c,v 1.17 2000/01/
 #include <rpc/pmap_prot.h>
 #include <sys/socket.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <unistd.h>
-#include <sys/mbuf.h>
 #include <net/if.h>
 #include <sys/ioctl.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
 
+
+/*
+ * Determine the size of an ifreq structure when addresses larger 
+ * than the pifreq structure size may be returned from the kernel.
+ */
+static size_t ifreqSize ( struct ifreq *pifreq )
+{
+  size_t size = pifreq->ifr_addr.sa_len + sizeof(pifreq->ifr_name);
+  if ( size < sizeof ( *pifreq ) ) {
+    size = sizeof ( *pifreq );
+  }
+  return size;
+}
+
 /*
  * don't use gethostbyname, which would invoke yellow pages
  *
@@ -63,28 +77,32 @@ get_myaddress(
 	struct sockaddr_in *addr)
 {
 	int s;
-	char buf[BUFSIZ];
 	struct ifconf ifc;
-	struct ifreq ifreq, *ifr, *end;
+	struct ifreq ifreq, *ifr;
 	int loopback = 0, gotit = 0;
 
 	if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
 		return(-1);
 	}
-	ifc.ifc_len = sizeof (buf);
-	ifc.ifc_buf = buf;
+again:
+	ifc.ifc_len = sizeof ( struct ifreq ) * 8u;
+	ifc.ifc_buf = malloc ( ifc.ifc_len );
+  if ( ! ifc.ifc_buf ) {
+		_RPC_close(s);
+    return -1;
+  }
 	if (ioctl(s, SIOCGIFCONF, (char *)&ifc) < 0) {
 		_RPC_close(s);
+    free ( ifc.ifc_buf );
 		return(-1);
 	}
-again:
 	ifr = ifc.ifc_req;
-	end = (struct ifreq *) (ifc.ifc_buf + ifc.ifc_len);
 
-	while (ifr < end) {
-		ifreq = *ifr;
-		if (ioctl(s, SIOCGIFFLAGS, (char *)&ifreq) < 0) {
+	while ( ifc.ifc_len >= ifreqSize ( ifr ) ) {
+    ifreq = *ifr;
+		if (ioctl(s, SIOCGIFFLAGS, (char *) &ifreq ) < 0) {
 			_RPC_close(s);
+      free ( ifc.ifc_buf );
 			return(-1);
 		}
 		if (((ifreq.ifr_flags & IFF_UP) &&
@@ -98,16 +116,21 @@ again:
 			gotit = 1;
 			break;
 		}
-		if (ifr->ifr_addr.sa_len)
-			ifr = (struct ifreq *) ((caddr_t) ifr +
-			      ifr->ifr_addr.sa_len -
-			      sizeof(struct sockaddr));
-		ifr++;
+
+    const size_t len = ifreqSize ( ifr );
+    ifc.ifc_len -= len;
+    /* 
+     * RTEMS seems to require copy up to properly aligned 
+     * boundary at the beginning of the buffer?
+     */
+    memmove ( ifr, len + (char *) ifr, ifc.ifc_len );
 	}
 	if (gotit == 0 && loopback == 0) {
+    free ( ifc.ifc_buf );
 		loopback = 1;
 		goto again;
 	}
 	(void)_RPC_close(s);
+  free ( ifc.ifc_buf );
 	return (gotit ? 0 : -1);
 }